What are the pros and cons of open sourcing my website’s code?

I’m afraid if you’re expecting to open source your code as a magic bullet to get others to work on improving it for free you are likely to be disappointed.

A successful open source project does not spring up over-night thanks to some code being released in to the world. First, you have to be solving a problem that many other developers also need to solve—and you need to be doing it well enough that they will find it more productive to start off with your solution rather than rolling their own from scratch (and many developers love rolling their own!)

Secondly, as the saying goes “if your ideas are any good you’ll have to ram them down people’s throats”—you’ll have to market your project: explain why it’s useful and worth contributing to, and get the message out to the right people.

Finally, you’ll have to maintain the project—answer support queries, merge patches, fix bugs reported by others.

Open sourcing code is no guarantee that others will do your work for free. Sure, it can work like that—most of Django has now been written by the community, not the original committers for example—but that’s only thanks to literally years of hard work by representatives of the company that originally open sourced it building up that community and supporting that development process.